The present invention relates to a method and apparatus for detecting minute quantities of trace metals in water. More specifically, but without limitation thereto, the present invention relates to measuring lead concentration in water with a stopped flow electrochemical cell.
Heavy metals such as lead have received increasing recognition as serious threats to the environment and to human health. The effects of lead may not be acute, thus chronic toxicity is of particular concern because the metal accumulates in tissues over a period of long-term exposure. This may lead to mental and physical abnormalities, especially in children.
The detrimental effects of lead in the environment have long been recognized. Lead poisoning has been detected in waterfowl due to lead shot. The elimination of tetraethyl lead as an octane booster in gasoline was part of an effort to prevent this metal from further contaminating soil and water sources. However, the use of lead in glazes, paints, and coatings, for example, has occurred over long periods of time, and lead in pottery may have contributed to the demise of earlier civilizations.
As a result of past long-term use of lead in a wide range of products, it is difficult to avoid exposure to this element. Lead-solder joints in water pipes, for example, contribute to the lead content of drinking water. Modern interior paints are lead-free, but in older homes there may significant exposure to lead from older lead-based paints, even when such paint layers have been painted over with the newer lead-free paints. This practice has created a risk of lead toxicity for those groups most susceptible to lead poisoning, especially children.
The long-term effect of lead on the health of children is significant. This is of concern to parents as well as to health care professionals and the federal government. Programs being developed to detect the presence of harmful substances in the environment will undoubtedly encourage the discovery of rapid, reliable methods for detecting low levels of lead.
Instruments currently available for monitoring trace metals generally require highly trained personnel to perform relatively sophisticated techniques. Consequently, such analyses are performed in centralized laboratories set up for routine multiple analysis. There is a need, however, for instrumentation available for use in the field or even in homes, hospitals, and commercial housing that is portable and operable without requiring highly trained technical personnel.